import React,{useState,useCallback} from 'react';

const App = () => {
    let [count, setcount] = useState(0);
    return (
        <div>
            <div>
                <button onClick={() => {
                    count++
                    setcount(count)
                }}>
                    点击添加
                </button>
                我是数字{count}
            </div>
        </div>
    );
}

export default App;
